IMPORTANT REMIND: PLEASE MAKE SURE YOUR GRINDER OR POLISHERS SPINDLE IS 5/8"-11 THREAD. Please make sure that your grinder or polisher speed is below 5000 RPM when using with the pad holder / backer. (a) 1 Piece of B10 (3/8" / 10 mm) for 10 mm / 3/8 Inch high / thick granite marble concrete quartz glass countertop / vanit top edge bullnosing Diamond Brazed Router Bit to do Radius / Half / Demi / Roundover shape bullnose. The inner hole of this router bit is 7/8" to 5/8". it works with grinder or polisher with 5/8"-11 Thread spindle. Important Remind: Please make sure that your grinder or polisher speed is below 5000 RPM when using with it. (b) One Lock Ring Nuts and wrench set (the pairs of lock ring nut is necessary to attach the router bit to your 5/8"-11 thread spindle grinder / polisher). (c) 1 piece of 4" Velcro Backer / Pad Holder (5/8"-11 Thread). Important Remind: Please make sure that your grinder or polisher speed is below 5000 RPM when using with it. (d) 15 Pieces of 4 Inch Diamond Dry Polishing Pad for granite marble glass stone concrete: 2 X Grit 50 100 200 400 800 1500 3000, 1 X Buff.